It is known that hydroxy acids have a potential for the formation of polyesters. For instance, poly(meta-oxybenzoyl) can be derived from m-hydroxybenzoic acid [Gilkey and Caldwell, J. Appl. Polym. Sci. 2, 198 (1959)]; and a polyester derived from p-(2-hydroxyethyl)benzoic acid (no methyl side groups) has been reported (Cook, et al., Brit. Pat. No. 604,985, ICI). It appeared therefore conceivable that p-(1,1-dimethyl-2-hydroxyethyl)benzoic acid may also form a polyester. However, we found that the polyester that indeed formed has completely unexpected thermal properties, advantageous for practical purposes, namely a melting point (T.sub.m) allowing facile processing on conventional fiber and film melt extrusion equipment, combined with a comparatively high glass transition temperature (T.sub.g), high enough to allow uses in which retention of strength at temperatures above 100.degree. C. is important.